Before the Celtics faced the Bulls and following a pregame workout, Rondo said he is open to a rehabilitation stint with Maine of the NBA Development League and is getting “pretty close” after missing nearly a year with a torn right anterior cruciate ligament. “I’m better than last week when I talked to you guys,” he said, referring to his media session Dec. 22. “I’m still getting my endurance but I’m getting pretty close, feeling good, feeling better.” Rondo, who has traveled with the team and was cleared to practice three weeks ago, has been working out arduously to approach game shape, saying he does not want to return prematurely and suffer a setback.